Conduit fitting



" Feb. 4, 1930. G. MET-CALF, JR 1,745,941

GONDUIT FITTING Filed April 1928 A I'NVENTOR.

v ATTORNEY.

gageathreadless conduit 8.

Patented Feb. 4, 1930 V "UNITED STATES GEORGE R. METGALF, JR., OF ERIE,PENNSYLVANIA, ASSIGNOR TO ERIE MALLEABLE PATENT o FIcE IRON COMPANY, OFERIE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA GONDUIT rI'r'rnvGApplication filed April 4,

This invention is designed to form a con venient means for connectingconduits with conduit boxes, particularly knock-out boxes and isparticularly applicable to threadless conduits. Features and details ofthe invention will appear from the specification and claims.

A preferred embodiment of the invention is illustrated in theaccompanying drawings as follows Fig. 1 shows an elevation of thedevice, partly in section.

' Fig. 2 an end view of an expanding sleeve adapted to fit in aknock-out box opening.

Fig. 8 a side elevation, partly in section, of such expanding sleeve.

Fig. 4 an end view of a contracting sleeve.

Fig. 5 a side elevation of the same, partly in section.

1 marks a fitting box, as for instance, the wall .of a knock-out box. Itis provided with an opening 2. i

The inner end of an expanding sleeve 3 has slots 4 and it is providedwith a groove 5, the walls of which engage the walls of the opening 2.The forward'end of the sleeve is tapered on itsinner periphery and it isprovided with an internal screw thread 6 at its outer end.

A contractible sleeve 7 is arranged within the expansible sleeve 3 andis adapted to en- This contractible sleeve is made contractible by aslot 9 extending entirely through it and a series of slots 10 which leadfrom the inner end outwardly. The inner end is rounded, or provided witha wedging surface 11 adapted to engage against the tapered interiorsurface of the expanding sleeve. 12 engaging the screw thread 6. Thesleeves are provided with the wrench-holds 13 and 14. f

. relatively the contracting sleeve is forced against the taperedsurface of the expanding sleeve, the effect being to expand theexpanding sleeve into clamping engagement with the walls of the opening2 and to .con-

It is provided with a screw thread 1928. Serial No. 267,434.

' tract the contracting sleeve into clamping engagement with theconduit.

The contracting sleeve is provided with a guard shoulder 15 at its innerend.

What I claim as new is 1. In a conduit fitting, the combination of abody having a conduit opening; an expansible sleeve in the openingcomprising an outer annulus and a slotted inner portion arranged withinthe opening, the outer annulus having an internal screw thread, saidslotted portion being unthreaded and having a tapered inner surface; anda contractible sleeve in the expansible sleeve, said 'contractiblesleeve the expansible sleeve, said contractible sleeve 7 having slotsand a wedging surface engaging the tapered surface of the expansiblesleeve and provided with a screw thread operating in the screw thread ofthe expansible sleeve and wrench holds on the outer ends of saidsleeves.

In testimony whereof I have hereunto set my hand. i

GEORGE R. METCALF, JR.

